Some work vehicles such as the wheel loaders are embedded with a torque converter unit including a torque converter and a lock-up clutch. When the lock-up clutch is set to be in a decoupled state, the torque converter unit is configured to transmit driving force from an engine to a drive unit through the torque converter (this state will be hereinafter referred to as “a torqcon state”). When the lock-up clutch is set to be in a coupled state, by contrast, the torque converter unit is configured to transmit driving force from the engine to the drive unit through the lock-up clutch (this state will be hereinafter referred to as “a lock-up state”). Further, a control unit is herein configured to automatically switch the lock-up clutch between the coupled state and the decoupled state. For example, the control unit is configured to switch the lock-up clutch from the decoupled state to the coupled state when the vehicle speed reaches a predetermined switching speed (see Japan Laid-open Patent Application Publication No. JP-A-2009-103258). Immediately after starting moving at a low vehicle speed, in particular, the work vehicle is configured to travel in the torqcon state for preventing an engine stall.